Another good thing is to teach them how to use programs such as Aladin to access astronomical databases and how to use the program to interpret what the images they download mean. If you want to know about other programs like Aladin that the kids can download as well...it's always good to know about all the software available, just give me a buzz
Another idea which may interest you is to get access to remote observatories like
Global Rent a Scope. You can trial it out for free yourself and the normal rates are quite good.
Any other areas of astronomy which may be of interest I most probably have access to the websites in question (or the information via textbooks), so feel free to ask and I can give them to you. Especially sites pertaining to astronomical theory and if you do get stuck with any of it, don't hesitate to ask me questions